Magnetic field sensing element combining a circular vertical hall magnetic field sensing element with a planar hall element

ABSTRACT

A magnetic field sensor includes a circular vertical Hall (CVH) sensing element and at least one planar Hall element. The CVH sensing element has contacts arranged over a common implant region in a substrate. In some embodiments, the at least one planar Hall element is formed as a circular planar Hall (CPH) sensing element also having contacts disposed over the common implant region. A CPH sensing element and a method of fabricating the CPH sensing element are separately described.

CROSS REFERENCE TO RELATED APPLICATIONS

Not Applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

Not Applicable.

FIELD OF THE INVENTION

This invention relates generally to magnetic field sensing elements forsensing a direction of a magnetic field and, more particularly, to amagnitude field sensing that combines a circular vertical Hall (CVH)magnetic field sensing element with a planar Hall element.

BACKGROUND OF THE INVENTION

Various types of magnetic field sensing elements are known, includingHall effect elements and magnetoresistance elements. Magnetic fieldsensors generally include a magnetic field sensing element and otherelectronic components.

Some magnetic field sensing elements and associated magnetic fieldsensors provide an electrical signal representative of a direction of asensed magnetic field. The magnetic field signal varies in accordancewith the direction in a way that can be resolved to identify a pointingdirection of the magnetic field.

Most types of such direction-indicating magnetic field sensing elementsand associated magnetic field sensors generate signals that areindicative of the direction of a component of the magnetic field in onlytwo dimensions, i.e., in a plane. However, the magnetic field may have apointing direction not parallel to the plane of sensitivity of themagnetic field sensor, i.e., in three dimensions.

Magnetic field sensor that can sense three dimensions of a magneticfield are useful in some applications, for example, in three dimensionaljoysticks, where the joystick can be moved in two dimensions and alsocan be depressed in a third dimension. Some three-dimensionalapplications use both a magnetic field sensor operable to provide atwo-dimensional indication of a pointing direction of a magnetic fieldin a plane and also a separate one-dimensional magnetic field sensoroperable to provide indication of a magnitude of a magnetic field in adirection perpendicular to the plane.

Thus, to resolve some of the three-dimensional characteristics of themagnetic field, some arrangements use both a two-dimensional magneticfield sensor and also a one-dimensional magnetic field sensor. In someapplications, output signals from the two magnetic field sensors can befurther processed to provide a signal representative of a magnitude ofthe magnetic field along the three-dimensional pointing direction of themagnetic field. Thus, by combining information generated by the twomagnetic field sensors, three-dimensional characteristics of themagnetic field can be determined.

It is cumbersome to provide both the above-described two-dimensionalmagnetic field sensor and also the above described one-dimensionalmagnetic field sensor. A combination of two such magnetic field sensorstends to be expensive. Furthermore, additional processing is required toresolve the three-dimensional characteristics of the sensed magneticfield. Still further, alignment of the two types of magnetic fieldsensors to provide orthogonal axes is critical to the accuracy of theresulting resolved three-dimensional characteristics, and such alignmentcan be difficult and inaccurate.

Therefore, it would be desirable to provide a single integrated magneticfield sensing element and associated magnetic field sensor that cangenerate a signal or signals that is/are indicative of characteristicsof a magnetic field in three dimensions. In some embodiments, theintegrated magnetic field sensing element is formed upon a singlesubstrate, e.g., a silicon substrate, which tends to make it easier toprovide aligned axes.

SUMMARY OF THE INVENTION

The present invention provides a single integrated magnetic fieldsensing element and associated magnetic field sensor that can generate asignal or signals that is/are indicative of characteristics of amagnetic field in three dimensions. In some embodiments, the integratedmagnetic field sensing element is formed upon a single substrate, e.g.,a silicon substrate, which tends to make it easier to provide alignedaxes.

In accordance with one aspect of the present invention, a magnetic fieldsensor includes a semiconductor substrate having first and secondparallel major surfaces. The magnetic field sensor includes a pluralityof vertical Hall elements arranged as a circular vertical Hall (CVH)structure. Each one of the plurality of vertical Hall elements isarranged upon a common circular implant region in the first majorsurface of the semiconductor substrate. The plurality of vertical Hallelements is configured to generate a respective plurality of x-y outputsignals responsive to a magnetic field having a direction component inan x-y plane parallel to the first major surface of the semiconductorsubstrate, the x-y plane having an x-direction and a y-directionorthogonal to the x-direction. The magnetic field sensor also includes aplanar Hall element disposed upon the semiconductor substrate. Theplanar Hall element is configured to generate a z output signalresponsive to a magnetic field having a direction component in a zdirection orthogonal to the x-y plane. The magnetic field sensor alsoincludes a processing circuit disposed upon the semiconductor substrate,coupled to receive a signal representative of the plurality of x-youtput signals, coupled to receive a signal representative of the zoutput signal, configured to generate one or more of an x-y angle signalrepresentative of an angle of the direction component in the x-y-plane,or an x-y magnitude signal representative of a magnitude of thedirection component in the x-y plane, and configured to generate a zmagnitude signal representative of a magnitude of the directioncomponent in the z direction.

In some embodiments, the x-y angle signal, the x-y magnitude signal, andthe z-magnitude signal can be combined to generate a three-dimensionalsignal representative of a three-dimensional pointing direction of themagnetic field and/or a magnitude of the magnetic field along thethree-dimensional pointing direction.

In accordance with another aspect of the present invention, a magneticfield sensor includes a semiconductor substrate having first and secondparallel major surfaces parallel to an x-y plane. The magnetic fieldsensor also includes a plurality of planar Hall elements arranged as acircular planar Hall (CPH) structure. Each one of the plurality ofplanar Hall elements is arranged upon a common circular implant regionin the first major surface of the semiconductor substrate. The pluralityof planar Hall elements is configured to generate a plurality of zoutput signals responsive to a magnetic field having a directioncomponent in a z direction orthogonal to the x-y plane.

In accordance with another aspect of the present invention, a method offabricating a magnetic field sensing element arrangement includesforming a common circular implant region in a first major surface of asemiconductor substrate having the first and a second major parallelsurface both parallel to an x-y plane. The method also includes forming,over the common circular implant region, a plurality of planar Hallelements arranged as a circular planar Hall (CPH) structure. Theplurality of planar Hall elements is configured to generate a pluralityof z output signals responsive to a magnetic field having a directioncomponent in a z direction orthogonal to the x-y plane.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features of the invention, as well as the invention itselfmay be more fully understood from the following detailed description ofthe drawings, in which:

FIG. 1 is a pictorial showing a magnetic field sensor having a magneticfield sensing element arrangement with a circular vertical Hall (CVH)sensing element and a planar Hall element disposed over separate implantregions in a common substrate,

FIG. 2 is a pictorial showing a CVH sensing element having a pluralityof vertical Hall elements, each vertical Hall element having a pluralityof vertical Hall element contacts;

FIG. 2A is a pictorial showing a circular planar Hall (CPH) sensingelement having a plurality of planar Hall elements, each planar Hallelement having a plurality of planar Hall element contacts;

FIG. 2B is a pictorial showing a magnetic field sensing elementarrangement having a CVH sensing element and having a CPH sensingelement all disposed over a common implant region in a common substrate;

FIG. 3 is a block diagram showing a magnetic field sensor having amagnetic field sensing element arrangement with the CVH sensing elementand with a CPH sensing element in a combined arrangement, having an x-ydirection component circuit, having a z direction component circuit, andhaving a combining circuit;

FIG. 4 is a block diagram showing further details of the magnetic fieldsensor of FIG. 3;

FIG. 5 is a graph showing four signals within the magnetic field sensorof FIG. 4 and associated with the CVH sensing element;

FIG. 6 is a graph showing another three signals within the magneticfield sensor of FIG. 4 and associated with the CPH sensing element; and

FIG. 7 is a pictorial showing magnetic field sensor having a magneticfield sensing element arrangement with a CVH sensing element and a CPHsensing element.

DETAILED DESCRIPTION OF THE INVENTION

Before describing the present invention, some introductory concepts andterminology are explained.

As used herein, the term “magnetic field sensing element” is used todescribe a variety of electronic elements that can sense a magneticfield. The magnetic field sensing elements can be, but are not limitedto, Hall effect elements, magnetoresistance elements, ormagnetotransistors. As is known, there are different types of Halleffect elements, for example, a planar Hall element, a vertical Hallelement, and a circular Hall element. As is also known, there aredifferent types of magnetoresistance elements, for example, a giantmagnetoresistance (GMR) element, an anisotropic magnetoresistanceelement (AMR), a tunneling magnetoresistance (TMR) element, an Indiumantimonide (InSb) sensor, and a magnetic tunnel junction (MTJ).

A so-called “circular vertical Hall” (CVH) sensing element, is known anddescribed in PCT Patent Application No. PCT/EP2008056517, entitled“Magnetic Field Sensor for Measuring Direction of a Magnetic Field in aPlane,” filed May 28, 2008, and published in the English language as PCTPublication No. WO 2008/145662, which application and publicationthereof are incorporated by reference herein in their entirety. The CVHsensing element is a circular arrangement of vertical Hall elements(i.e., vertical Hall element contacts) arranged over a common circularimplant region in a substrate. The CVH sensing element can be used tosense a direction (i.e., an angle), and optionally a magnitude, of acomponent of a magnetic field in a plane of the substrate.

As is known, some of the above-described magnetic field sensing elementstend to have an axis of maximum sensitivity parallel to a substrate thatsupports the magnetic field sensing element, and others of theabove-described magnetic field sensing elements tend to have an axis ofmaximum sensitivity perpendicular to a substrate that supports themagnetic field sensing element. In particular, planar Hall elements tendto have axes of sensitivity perpendicular to a substrate, whilemagnetoresistance elements and vertical Hall elements (includingcircular vertical Hall (CVH) sensing elements) tend to have axes ofsensitivity parallel to a substrate.

Magnetic field sensors are used in a variety of applications, including,but not limited to, an angle sensor that senses an angle of a directionof a magnetic field, a current sensor that senses a magnetic fieldgenerated by a current carried by a current-carrying conductor, amagnetic switch that senses the proximity of a ferromagnetic object, arotation detector that senses passing ferromagnetic articles, forexample, magnetic domains of a ring magnet, and a magnetic field sensorthat senses a magnetic field density of a magnetic field.

Referring to FIG. 1, a magnetic field sensor 10 can include a magneticfield sensing element arrangement 11. The magnetic field sensing elementarrangement 11 includes a circular vertical Hall (CVH) sensing element12 disposed over a common implant region 16, which is disposed upon asubstrate 22. The CVH sensing element 12 includes a plurality ofvertical Hall elements, of which a vertical Hall element 14 is but oneexample. The vertical Hall element 14, like other vertical Hall elementsin the CVH sensing element 12, includes a plurality of vertical Hallelement contacts, of which vertical Hall element contacts 14 a, 14 b, 14c, 14 d, 14 e are examples. While the vertical Hall element 14 is shownhaving five vertical Hall element contacts 14 a, 14 b, 14 c, 14 d, 14 e,in other embodiments, a CVH sensing element can have vertical Hallelements with more than five or fewer than five vertical Hall elementcontacts, for example, four vertical Hall element contacts or sixvertical Hall element contacts.

The magnetic field sensing element arrangement 11 can also include aplanar Hall element 18 disposed upon the substrate 22, for example inthe center or near the center of the CVH sensing element 12. However,other placements of the planar Hall element 18 upon the substrate 22 arealso possible. The planar Hall element 18 is disposed over a separateimplant region 20.

The CVH sensing element 12 in conjunction with electronics 24, describedmore fully below, can provide an output signal 24 a representative ofone or more two dimensional aspects of a magnetic field. The one or moreaspects can include, for example, a) an angle of a direction of acomponent of a magnetic field experienced by the CVH sensing element 12in a plane of the CVH sensing element 12, and b) a magnitude of themagnetic field in the plane of the CVH sensing element 12.

In contrast, the planar Hall element 18 in conjunction with theelectronics 24 can provide the output signal 24 a representative of amagnitude of a component of the magnetic field in a directionperpendicular to a plane of the planar Hall element 18.

With the above information, the magnetic field sensing elementarrangement 11 in conjunction with the electronics 24 can providesufficient information to resolve some three-dimensional characteristicsof the magnetic field, for example, a) a three-dimensional pointingdirection of the magnetic field experienced by the magnetic fieldsensing element arrangement 10, and b) a magnitude of the magnetic fieldalong the three-dimensional pointing direction. In some embodiments, theresolution of the three-dimensional characteristics can be provided byanother processor (not shown) coupled to receive the signal 24 a.However, in some embodiments, the electronics 24 can provide the outputsignal 24 a representative of the three-dimensional pointing directionof the magnetic field and also the magnitude of the magnetic field inthe three-dimensional pointing direction.

Referring now to FIG. 2, a CVH sensing element 26 having a plurality ofvertical Hall elements, of which a vertical Hall element 28 is but oneexample, can be the same as or similar to the CVH sensing element 12 ofFIG. 1. The CVH sensing element 26 can include a common implant region27 in a substrate over which the plurality of vertical Hall elements,each having a plurality of vertical Hall element contacts, are disposed.Each vertical Hall element, for example, a vertical Hall element 28, caninclude a plurality of vertical Hall element contacts, for example, fivecontacts, 28 a, 28 b, 28 c, 28 d, 28 e.

Referring now to FIG. 2A, a circular planar Hall (CPH) sensing element30 can include a plurality of planar Hall elements, of which a planarHall elements 34 is but one example. The planar Hall elements can bedisposed over a common implant region 32 in a substrate. Each planarHall element, for example, the planar Hall element 34, can include aplurality of planar Hall element contacts, for example four contacts, 34a, 34 b, 34 c, 34 d.

Referring now to FIG. 2B, a magnetic field sensor 40 can include amagnetic field sensing element arrangement 41. The magnetic fieldsensing element arrangement 41 can include a CVH sensing element 48,which can be the same as or similar to the CVH sensing element 26 ofFIG. 2, and also a CPH sensing element 46, which can be the same as orsimilar to the CPH sensing elements 30 of FIG. 2A. The CVH sensingelement 48, which includes a plurality of vertical Hall elements, ofwhich a vertical Hall element 44 is but one example, is disposed over acommon implant region 42 upon a substrate 50. Also, the CPH sensingelement 46, which includes a plurality of planar Hall elements, of whicha planar Hall element 47 is but one example, is also disposed over thecommon implant region 42 upon the substrate 50. Each one of the planarHall elements of the CPH sensing element 46 can be disposed betweencontacts of the CVH sensing element.

It will be appreciated that, like the magnetic field sensor 10 of FIG.1, the magnetic field sensor 40 can include electronics 52, describedmore fully below, that can provide an output signal 52 a representativeof one or more two and/or three-dimensional characteristics of amagnetic field experienced by the magnetic field sensor 40. For example,the output signal 52 a can provide information representative of one ormore of a) an angle of a direction of a component of a magnetic fieldexperienced by the magnetic field sensing element arrangement 41 in aplane of the CVH sensing element 48, b) a magnitude of the component ofthe magnetic field in the plane of the CVH sensing element 48, c) amagnitude of a component of the magnetic field in a directionperpendicular to a plane of the CPH sensing element 46, d) athree-dimensional pointing direction of the magnetic field experiencedby the magnetic field sensing element arrangement 41, and e) a magnitudeof the magnetic field along the three-dimensional pointing direction.

In some alternate embodiments, the CVH sensing element 48 and the CPHsensing element 46 are disposed over different implant regions. In somealternate embodiments, there are fewer planar Hall elements such that aplanar Hall element is not disposed between every pair of vertical Hallelement contacts.

Shown optionally, by way of phantom lines, as described above, insteadof the CVH sensing element 48, the sensing element arrangement 41 canhave a CVH sensing element 54 disposed over a separate common implantregion 56, separate from the common implant region 42 over which the CPHsensing element 46 is disposed. In the CVH sensing element 54, only twovertical Hall element contacts, e.g., 58, are shown for clarity.

While the optional CVH sensing element 54 is shown to have a smallerdiameter disposed over a smaller diameter common implant region than theCPH sensing element 46, in other embodiments, an optional CVH sensingelement can have a larger diameter and be disposed over a largerdiameter common implant region than the CPH sensing element 46. In someembodiments, the optional CVH sensing element 54 is disposed on anopposite side of the substrate 50 from the CPH sensing element 46.

Referring now to FIG. 3, a magnetic field sensor 50 can include amagnetic field sensing element arrangement 52, which can include acombination of a CVH sensing element an a CPH sensing element like themagnetic field sensing element arrangement 41 of FIG. 2B. In otherembodiments, the magnetic field sensing element arrangement 52 can belike the magnetic field sensing element arrangement 11 of FIG. 1.

An oscillator 58 is configured to generate a clock signal 58 a. Switchesand logic 56 are coupled to provide control signals 56 a to the magneticfield sensing element arrangement 52. The switching and control of a CVHsensing element are described more fully in the above-mentioned PCTPatent Application No. PCT/EP2008056517. Switching and control of a CPHsensing element is similar to that of a CVH sensing element. Both aredescribed more fully below in conjunction with FIG. 7.

A bias circuit 54 is configured to provide one or more bias signals 54 ato the magnetic field sensing element arrangement 52. In someembodiments, the one or more bias signals 54 a are current signals.

The magnetic field sensing element arrangement 52 is configured togenerate an output signal 52 a representative of an angle and amagnitude of a component of the magnetic field experienced by themagnetic field sensing element arrangement 52 in a plane (an x-y plane)of the magnetic field sensing element arrangement 52. The magnetic fieldsensing element arrangement 52 is also configured to generate an outputsignal 52 b representative of a magnitude of a component of the magneticfield experienced by the magnetic field sensing element arrangement 52in a direction perpendicular to the plane of magnetic field sensingelement arrangement 52.

An x-y direction component circuit 60 is coupled to receive the signal52 a and configured to generate a signal 60 a representative of theangle of the component of the magnetic field experienced by the magneticfield sensing element arrangement 52 in the plane of the magnetic fieldsensing element arrangement 52, and can be representative of themagnitude of the component of the magnetic field in the plane of themagnetic field sensing element arrangement 52. A z direction componentcircuit 62 is coupled to receive the signal 52 b and configured togenerate a signal 62 a representative of the magnitude of the componentof the magnetic field experienced by the magnetic field sensing elementarrangement 52 in the direction perpendicular to the plane of thesensing element and arrangement 52.

A combining processor 64 is coupled to receive the signals 60 a, 62 a,and configured to generate an output signal 64 a, which can be signalrepresentative of all of the above directional characteristics. In someembodiments, the output signal can also or instead be representative ofa three-dimensional pointing direction of the magnetic field and/or amagnitude of the magnetic field along the three-dimensional pointingdirection.

Operation of the magnetic field sensor 50 is more fully described belowin conjunction with FIG. 4.

Referring now to FIG. 4, a magnetic field sensor 100 includes a magneticfield sensing element arrangement 102 having a CVH sensing element 104with a plurality of vertical Hall elements and a CPH sensing element 106with a plurality of planar Hall elements, like the magnetic fieldsensing element arrangement 41 of FIG. 2B. In other embodiments, themagnetic field sensing element arrangement 102 can be like the magneticfield sensing element arrangement 11 of FIG. 1.

Current sources 108 a, 108 b, 108 c, 108 d can provide bias signals inthe form of current signals 108 aa, 108 ba, 108 ca, 108 da to themagnetic field sensing element arrangement 102.

An oscillator 112 can generate a clock signal 112 a. A divider 114 canbe coupled to receive the clock signal 112 a and configured to generatea divided clock signal 114 a. A switch control circuit 110 can becoupled to receive the divided clock circuit 114 a and configured togenerate control signals 110 a. A switching circuit 116 is coupled toreceive the control signals 110 a and configured to operate the magneticfield sensing element arrangement 102 in ways more fully describedbelow.

Operation of the CVH sensing element part 104 of the magnetic fieldsensing element arrangement 102 is more fully described in theabove-described PCT Publication No. WO 2008/145662.

The magnetic field sensing element arrangement 102, and, in particular,the CVH sensing element 104, is configured to generate a differentialsignal 104 a, 104 b, which includes a plurality of so-called “x-y outputsignals.” The magnetic field sensing element arrangement 102, and, inparticular, the CPH sensing element 106, is also configured to generatea differential signal 106 a, 106 b, which includes a plurality ofso-called “z output signals.”

The magnetic field sensor 100 can include an x-y direction componentcircuit 118, which can be the same as or similar to the x-y directioncomponent circuit 60 of FIG. 3. The x-y direction component circuit 118can include an amplifier 120 coupled to receive the differential signal104 a, 104 b and configured to generate an amplified signal 120 a (alsoreferred to herein as a first intermediate signal). A bandpass filter122 is coupled to receive the amplified signal 120 a and configured togenerate a filtered signal 122 a. A comparator 126, with or withouthysteresis, is coupled to receive the filtered signal 122 a. Thecomparator 126 is also coupled to receive a threshold signal 124. Thecomparator 126 is configured to generate a thresholded signal 126 aresponsive to a comparison between the filtered signal 122 a and athreshold signal 124.

The x-y direction component circuit 118 can also include a counter 128coupled to receive the thresholded signal 126 a at an enable input.

The oscillator 112 is also configured to generate clock signals 112 band 112 c. A divider 113 is coupled to receive the clock signal 112 cand configured to generate another divided clock signal 113 a.

The counter 128 is coupled to receive the clock signal 112 b at a clockinput and coupled to receive the divided clock signal 113 a at a resetinput.

In operation, the counter 128 is configured to generate a count signal128 a, which is a multi-bit digital signal representative of a phasedifference between the thresholded signal 126 a and the divided clocksignal 113 a. Thus, the count signal 128 a is representative of an angleof a direction of a component of the magnetic field experienced by theCVH sensing element 104 in a plane of the CVH sensing element 104, whichis also referred to herein as an x-y plane.

The x-y direction component circuit 118 can also include a latch 130coupled to receive the count signal 128 a and configured to generate alatched signal 130 a, which, like the count signal 128 a, isrepresentative of the angle of the direction of the component of themagnetic field experienced by the CVH sensing element 104 in the x-yplane of the CVH sensing element 104.

The x-y direction component circuit 118 can also include an amplitudedetection circuit. The amplitude detection circuit can include arectifier 132 coupled to receive the filtered signal 122 a andconfigured to generate a rectified signal 132 a. The amplitude detectioncircuit can also include a low pass filter 134 coupled to receive therectified signal 132 a and configured to generate a low pass filteredsignal 134 a. An analog-to-digital converter 136 can be coupled toreceive the low pass filtered signal 134 a and configured to generate asignal 136 a, which is representative of a magnitude the component ofthe magnetic field experienced by the CVH sensing element 104 in the x-yplane. Other circuit topologies can also be used to detect amplitude.

The magnetic field sensor 100 can also include a z direction componentcircuit 138 having an amplifier 140 coupled to receive the differentialsignal 106 a, 106 b. The amplifier 140 is configured to generate anamplified signal 140 a (also referred to herein as a second intermediatesignal). A low pass filter 142 is coupled to receive the amplifiedsignal 140 a and configured to generate a filtered signal 142 a. Ananalog-to-digital converter 144 is coupled to receive the filteredsignal 142 a and configured to generate a z magnitude signal 144 a,which is representative of a magnitude of a component of the magneticfield experienced by the CPH sensing element 106 in a directionperpendicular to the x-y plane. Other circuit topologies can also beused to detect the z-magnitude.

The signals 136 a, 130 a, 144 a can be provided to a combiningprocessor, for example, the combining processor 64 of FIG. 3. In someembodiments, the combining processor is configured to format one or moreof the signals 130 a, 136 a, 144 a into a standard format forcommunication to circuits outside of the magnetic field sensor. Theformat can be one of a variety of formats, including, but not limitedto, a SENT format, an I2C format, or a pulse width modulated (PWM)format. In other embodiments, the combining processor is furtherconfigured to process the signals 130 a, 136 a, 144 a to generate one ormore of a signal representative of a pointing direction of the magneticfield in three dimensions, for example, an angle relative to the x-yplane, or a signal representative of a magnitude of the magnetic fieldsignal along the three-dimensional pointing direction. These signals canalso be put into one of the above standard formats for communicationwith the above-described signals or in place of the above-describedsignals.

Referring now to FIG. 5, a graph 150 has a horizontal axis with unitsrepresentative of a vertical Hall element position around the CVHsensing element 104 of FIG. 4. Vertical Hall element position isdiscussed more fully below in conjunction with FIG. 7. As will beunderstood from discussion below in conjunction with FIG. 7, in anexemplary embodiment there can be sixty-four vertical Hall elementcontacts in the CVH sensing element 104 and a corresponding sixty-fourvertical Hall elements in the CVH sensing element 104.

The graph 150 also includes a vertical axis having units of volts infour different ranges corresponding to four different signals 152, 154,156, 158.

The signal 152 is representative of the clock signal 112 b of FIG. 4.The signal 154 is representative of the divided clock signal 113 a ofFIG. 4. The signal 156 is representative of the amplified signal 120 aof FIG. 4. The signal 158 is representative of the filtered signal 122 aof FIG. 4.

It should be understood that the signal 154 is a fixed reference signalthat does not change phase in relation to a direction of a magneticfield. However, the signals 156 and 158 do change phase in relation tothe direction of the magnetic field in the plane of a corresponding CVHsensing element. The phase difference between that of the signal 154 andthat of the signals 156, 158 is representative of an angle of themagnetic field in a plane of the CVH sensing element.

From the signal 158, it can be seen that different ones of the verticalHall elements within the CVH sensing element 104 provide signals withdifferent amplitudes relative to zero when in the presence of a magneticfield. A maximum negative signal is achieved at vertical Hall elementposition number 24 and a maximum positive signal is achieved at verticalHall element position number 56. A phase of the signal 158, i.e., asensing element position of the maxima and minima, is related to theangle of the direction of a component of the magnetic field experiencedby the CVH sensing element 104 in the plane of the CVH sensing element104 (FIG. 4). Thus, for other angles of the magnetic field, the phasewill be different, and the maxima and minima (and also the zerocrossings) will be at different vertical Hall element positions.

With regard to the signal 156, the irregular up-and-down excursions ofthe signal 156 are representative of DC offset signals that vary amongthe vertical Hall elements of the CVH sensing element 104. The offsetvoltages are undesirable.

A magnitude B_(xy) of the signal 158 is representative of the magnitudeof the component of the magnetic field experienced by the CVH sensingelement 104 of FIG. 4 in the plane of the CVH sensing element 104.

Referring now to FIG. 6, graph 170 has a horizontal axis with unitsrepresentative of a planar Hall element position around the CPH sensingelement 106 of FIG. 4. As will be understood from discussion below inconjunction with FIG. 7, in an exemplary embodiment there can besixty-four planar Hall elements in the CPH sensing element 106 and twohundred fifty six planar Hall element contacts in the CPH sensingelement 106.

The graph 170 also includes a vertical axis having units of volts inthree different ranges corresponding to three different signals 172,174, 176.

The signal 172, like the signal 152 of FIG. 5, is representative of theclock signal 112 b of FIG. 4. The signal 174 is representative of theamplified signal 140 a of FIG. 4. The signal 176 is representative ofthe filtered signal 142 a of FIG. 4.

A magnitude 13, of the signal 176 is representative of a magnitude of acomponent of the magnetic field experienced by the CPH sensing element106 in a direction perpendicular to the plane of the CPH sensing element106.

Referring now to FIG. 7, a magnetic field sensor 200 includes a magneticfield sensing element arrangement 201. The magnetic field sensingelement arrangement 201 includes a circular implant region 202 in asurface of a substrate 208. A plurality of vertical Hall elements, ofwhich vertical Hall elements 204 a, 204 b, 204 c are examples, isdisposed upon the circular implant region 202. Each vertical Hallelement has a plurality of Hall element contacts (e.g., four or fivecontacts), of which a vertical Hall element contact 204 aa is but oneexample.

A particular vertical Hall element (e.g., 204 a) within the CVH sensing,which, for example, can have five adjacent contacts, can share some, forexample, four, of the five contacts with a next vertical Hall element(e.g., 204 b). Thus, a next vertical Hall element 204 b can be shiftedby one contact from a prior vertical Hall element. For such shifts byone contact, it will be understood that the number of vertical Hallelements is equal to the number of vertical Hall element contacts, e.g.,sixty-four. However, it will also be understood that a next verticalHall element can be shifted by more than one contact from the priorvertical Hall element, in which case, there are fewer vertical Hallelements than there are vertical Hall element contacts in the CVHsensing element.

In an exemplary CVH sensing element, there are sixty-four vertical Hallelements and sixty-four vertical Hall element contacts. However, a CVHcan have more than or fewer than sixty-four vertical Hall elements andmore than or fewer than sixty-four vertical Hall element contacts.

The magnetic field sensing element arrangement 201, like the magneticfield sensing element arrangement 41 of FIG. 2B, can also include aplurality of planar Hall elements, for example, planar Hall elements 206a, 206 b, 206 c, 206 d, 206 e.

Each planar Hall element can have, for example, four contacts, which arerepresented by dots. In some embodiments contacts of planar Hallelements are essentially shared. For example, in one embodiment a firstplanar Hall element 206 a has four contacts. A next planar Hall element206 b shares two of the contacts of the planar Hall element 206 a. Anext planar Hall element 206 c shares two of the contacts of the planarHall element 206 b, and so on.

In other embodiments, contacts of adjacent planar Hall elements are notshared. For example, a first planar Hall element 206 a can share nocontacts with a next planar Hall element 206 c.

In some embodiments, each vertical Hall element (e.g., five verticalHall element contacts) is chopped. Chopping will be understood to be aswitching arrangement that reconfigures the current drive signals to thecontacts of a vertical Hall element and reconfigures the output signalcontacts of a vertical Hall element, most often in four configurations,one at a time, to provide an output signal from the vertical Hallelement sequentially representative of the four configurations. Choppingtends to result in a reduction of the effect of offset voltages of thevertical Hall elements discussed above in conjunction with the signal156 of FIG. 5.

Similarly, in some embodiments, each planar Hall element (e.g., fourplanar Hall element contacts) is chopped to achieve the same benefit.However, in other embodiments no chopping is used, in which case, onlyone configuration of drive and output contacts is used for each verticalor planar Hall element.

While sixty-four vertical Hall elements and sixty-four planar Hallelements are described in CVH and CPH sensing elements above, it will beunderstood that there can be more than or fewer than sixty-four oreither type of Hall elements in the magnetic field sensing elementarrangements described above, including embodiments that have unequalnumbers of vertical Hall elements

All references cited herein are hereby incorporated herein by referencein their entirety. Having described preferred embodiments, which serveto illustrate various concepts, structures and techniques, which are thesubject of this patent, it will now become apparent to those of ordinaryskill in the art that other embodiments incorporating these concepts,structures and techniques may be used. Accordingly, it is submitted thatthat scope of the patent should not be limited to the describedembodiments but rather should be limited only by the spirit and scope ofthe following claims.

1. A magnetic field sensor, comprising: a semiconductor substrate havingfirst and second parallel major surfaces; a plurality of vertical Hallelements arranged as a circular vertical Hall (CVH) structure, whereineach one of the plurality of vertical Hall elements is arranged upon acommon circular implant region in the first major surface of thesemiconductor substrate, wherein the plurality of vertical Hall elementsis configured to generate a respective plurality of x-y output signalsresponsive to a magnetic field having a direction component in an x-yplane parallel to the first major surface of the semiconductorsubstrate, the x-y plane having an x-direction and a y-directionorthogonal to the x-direction; a planar Hall element disposed upon thesemiconductor substrate, wherein the planar Hall element is configuredto generate a z output signal responsive to a magnetic field having adirection component in a z direction orthogonal to the x-y plane; and aprocessing circuit disposed upon the semiconductor substrate, coupled toreceive a signal representative of the plurality of x-y output signals,coupled to receive a signal representative of the z output signal,configured to generate one or more of an x-y angle signal representativeof an angle of the direction component in the x-y-plane, or an x-ymagnitude signal representative of a magnitude of the directioncomponent in the x-y plane, and configured to generate a z magnitudesignal representative of a magnitude of the direction component in the zdirection.
 2. The magnetic field sensor of claim 1, wherein the planarHall element is one of a plurality of planar Hall elements disposed uponthe semiconductor substrate, wherein the plurality of planar Hallelements is configured to generate a plurality of z output signalsresponsive to the magnetic field having the direction component in the zdirection, and wherein the processing circuit is coupled to receive asignal representative of the plurality of z output signals.
 3. Themagnetic field sensor of claim 2, wherein the plurality of planar Hallelements is arranged in a circular planar Hall (CPH) structure, whereineach one of the plurality of planar Hall elements is arranged upon thecommon circular implant region.
 4. The magnetic field sensor of claim 3,wherein the common circular implant region comprises n-type dopingmaterial and wherein the substrate is comprised of p-type material. 5.The magnetic field sensor of claim 4, wherein the semiconductorsubstrate comprises a silicon substrate.
 6. The magnetic field sensor ofclaim 3, wherein each one of the plurality of planar Hall elementscomprises a respective group of planar Hall element contacts, whereinthe processing circuit is operable to process the plurality of planarHall elements using a plurality of groups of the planar Hall elementcontacts to generate the signal representative of the plurality of zoutput signals.
 7. The magnetic field sensor of claim 6, wherein theprocessing circuit is further operable to process each group of planarHall element contacts in a multiplexed arrangement, wherein differentones of the planar Hall element contacts of each one of the plurality ofplanar Hall elements provide different ones of the plurality of z outputsignals at different times.
 8. The magnetic field sensor of claim 6,wherein each one of the plurality of vertical Hall elements comprises arespective group of vertical Hall element contacts, wherein theprocessing circuit is operable to process the plurality of vertical Hallelements using a plurality of groups of vertical Hall element contactsto generate the signal representative of the plurality of x-y outputsignals.
 9. The magnetic field sensor of claim 8, wherein the processingcircuit is operable to process each group of vertical Hall elementcontacts in a multiplexed arrangement, wherein different ones of thevertical Hall element contacts of each one of the plurality of verticalHall elements provide different ones of the plurality of x-y outputsignals at different times.
 10. The magnetic field sensor of claim 8,wherein the processing circuit comprises a z direction componentprocessor coupled to receive the signal representative of the pluralityof z output signals and configured to generate a first intermediatesignal responsive to the direction component of the magnetic field inthe z direction.
 11. The magnetic field sensor of claim 10, wherein thefirst intermediate signal comprises a DC signal component having a DCsignal value responsive to a magnitude of the direction component of themagnetic field in the z direction, wherein the processing circuit isoperable to generate the z magnitude signal indicative of the magnitudeof the direction component of the magnetic field in the z directionresponsive to the DC signal value.
 12. The magnetic field sensor ofclaim 10, wherein the processing circuit further comprises an x-ydirection component processor coupled to receive the signalrepresentative of the plurality of x-y output signals and configured togenerate a second intermediate signal responsive to the directioncomponent of the magnetic field in the x-y plane.
 13. The magnetic fieldsensor of claim 12, wherein the second intermediate signal comprises anAC signal component having a phase responsive to an angle of thedirection component of the magnetic field in the x-y plane and having amagnitude responsive to a magnitude of the direction component of themagnetic field in the x-y plane, wherein the processing circuit isoperable to generate the x-y angle signal indicative of the angle of thedirection component of the magnetic field in the x-y plane in responseto the phase of the AC signal component.
 14. The magnetic field sensorof claim 13, wherein the processing circuit is further operable togenerate the x-y magnitude signal indicative of the magnitude of thedirection component of the magnetic field in the x-y plane in responseto the magnitude of the AC signal component.
 15. The magnetic fieldsensor of claim 12, wherein the z direction component processorcomprises a low pass filter coupled to receive a signal representativeof the first intermediate signal.
 16. The magnetic field sensor of claim12, wherein the x-y direction component processor comprises: a bandpassfilter coupled to receive a signal representative of the secondintermediate signal and configured to generate a filtered signal; and acounter circuit coupled to receive the filtered signal, coupled toreceive a clock signal, and configured to compare a phase of the clocksignal with a phase of the filtered signal.
 17. The magnetic fieldsensor of claim 16, wherein the x-y direction component processorfurther comprises an amplitude detector coupled to receive the filteredsignal and configured to detect an amplitude of the filtered signal togenerate an x-y magnitude signal representative of a magnitude of thedirection component of the magnetic field in the x-y plane.
 18. Themagnetic field sensor of claim 16, wherein the amplitude detectorcomprises a rectifier coupled to a low pass filter.
 19. The magneticfield sensor of claim 17, further comprising a combining processorcoupled to receive the z magnitude signal, the x-y angle signal, and thex-y magnitude signal, and configured to combine the signals to generatea signal representative of a magnitude of the magnetic field along itspointing direction in three dimensions.
 20. The magnetic field sensor ofclaim 17, further comprising a combining processor coupled to receive atleast two of the z magnitude signal, the x-y angle signal, or the x-ymagnitude signal and configured to format the at least two signals intoa format comprising at least one of a SENT format, an I2C format, or apulse width modulated (PWM) format.
 21. A magnetic field sensing elementarrangement, comprising: a semiconductor substrate having first andsecond parallel major surfaces parallel to an x-y plane; and a pluralityof planar Hall elements arranged as a circular planar Hall (CPH)structure, wherein each one of the plurality of planar Hall elements isarranged upon a common circular implant region in the first majorsurface of the semiconductor substrate, wherein the plurality of planarHall elements is configured to generate a plurality of z output signalsresponsive to a magnetic field having a direction component in a zdirection orthogonal to the x-y plane.
 22. The magnetic field sensingelement arrangement of claim 21, wherein the common circular implantregion comprises n-type doping material and wherein the substrate iscomprised of p-type material.
 23. The magnetic field sensing elementarrangement of claim 21, wherein the semiconductor substrate comprises asilicon substrate.
 24. The magnetic field sensing element arrangement ofclaim 21, further comprising a processing circuit disposed upon thesemiconductor substrate and coupled to receive a signal representativeof the plurality of z output signals, wherein each one of the pluralityof planar Hall elements comprises a respective group of planar Hallelement contacts, wherein the processing circuit is operable to processthe plurality of planar Hall elements using a plurality of groups of theplanar Hall element contacts to generate a signal representative of theplurality of z output signals.
 25. The magnetic field sensing elementarrangement of claim 24, wherein the processing circuit is furtheroperable to process each group of planar Hall element contacts in amultiplexed arrangement, wherein different ones of the planar Hallelement contacts of each one of the plurality of planar Hall elementsprovide different ones of the plurality of z output signals at differenttimes.
 26. The magnetic field sensing element arrangement of claim 24,wherein the processing circuit comprises a z direction componentprocessor coupled to receive the signal representative of the pluralityof z output signals and configured to generate an intermediate signalresponsive to the direction component of the magnetic field in the zdirection, wherein the intermediate signal comprises a DC signalcomponent having a DC signal value responsive to a magnitude of thedirection component of the magnetic field in the z direction, whereinthe processing circuit is operable to generate an output signalindicative of the magnitude of the direction component of the magneticfield in the z direction responsive to the DC signal value.
 27. Themagnetic field sensing element arrangement of claim 21, furthercomprising a circular vertical Hall (CVH) sensing element disposed uponthe common circular implant region, wherein the CVH sensing elementcomprises a plurality of vertical Hall element contacts, and wherein theplurality of planar Hall elements includes individual planar Hallelements interposed with the vertical Hall element contacts.
 28. Themagnetic field sensing element arrangement of claim 21, furthercomprising a circular vertical Hall (CVH) sensing element disposed upona different common circular implant region in a major surface of thesemiconductor substrate, wherein the CVH sensing element comprises aplurality of vertical Hall element contacts.
 29. A method of fabricatinga magnetic field sensing element arrangement, comprising: forming acommon circular implant region in a first major surface of asemiconductor substrate having the first and a second major parallelsurface both parallel to an x-y plane; and forming, over the commoncircular implant region, a plurality of planar Hall elements arranged asa circular planar Hall (CPH) structure, wherein the plurality of planarHall elements is configured to generate a plurality of z output signalsresponsive to a magnetic field having a direction component in a zdirection orthogonal to the x-y plane.
 30. The method of claim 29,further comprising: forming a circular vertical Hall (CVH) sensingelement disposed upon the common circular implant region, wherein theCVH sensing element comprises a plurality of vertical Hall elementcontacts, and wherein the plurality of planar Hall elements includesindividual planar Hall elements interposed with the vertical Hallelement contacts.
 31. The method of claim 29, further comprising:forming a circular vertical Hall (CVH) sensing element disposed upon adifferent common circular implant region in a major surface of thesemiconductor substrate, wherein the CVH sensing element comprises aplurality of vertical Hall element contacts.